What does electrotherapy decrease?

• A. ROM
• B. Blood flow
• C. Pain
• D. Muscle density

Answer: (C)

Electrotherapy primarily reduces pain by altering how the nervous system processes sensory input. Stimulation of sensory afferents can inhibit nociceptive signals at the spinal cord level (gate control), and it can also engage the body's pain-relief systems (endogenous opioids and descending pathways). This analgesic effect is the main reason to use electrotherapy in rehabilitation, as less pain allows more effective participation in exercises and activities.

ROM isn’t decreased by electrotherapy; in fact, pain relief from the therapy often enables greater range of motion during treatment. The goal isn’t to lower blood flow or tissue density either—electrotherapy doesn’t reduce muscle density, and it can even help with circulation or conditioning depending on the modality and use.